All Eyes on ADS-B: What Part 25 Operators Need to Know About DO-260B

In the Part 25 retrofit market you see a lot of different configurations to start with, therefore there’s no one cookie-cutter approach you can get to put in an ADS-B system.— Mark Francetic, Duncan Aviation

All Part 25 business aviation operators have Automatic Dependent Surveillance-Broadcast (ADS-B) Out technology on their radar as mandated avionics equipage required before the end of this decade. The FAA passed regulation in 2010, as part of its Next Generation Air Transportation System (NextGen) initiative, requiring all operators flying aircraft in Class A, B and C airspace, as well as Class E airspace in areas at or above 10,000 feet over the 48 contiguous states, to equip with the necessary avionics to implement ADS-B Out capabilities. This effectively made equipage necessary for air transport category aircraft flying in the U.S. by Jan. 1, 2020. Similarly, the European Aviation Safety Administration (EASA), as part of its the Single European Sky ATM Research Joint Undertaking (SESAR JU) initiative, outlined ADS-B compliance along similar standards. The deadline for retrofit aircraft flying in European airspace to comply was recently pushed back to match the deadline for U.S. compliance.

The new technology aims to make the switch from legacy radar to satellite based airspace surveillance. This will enable regulators and operators to move forward with NextGen and SESAR efforts to modify the current Air Traffic Control (ATC) system, which aims to reduce delays and fuel use, shorten routes, monitor aircraft with greater safety margins, and increase capacity as the United States and Europe face rising airspace congestion in coming years.

“The overall improvement in update rate, accuracy, etc., is expected to be able to support advanced operations. However, … at this stage, the first steps in terms of ADS-B are about basically continuing to support current operations with a more both cost- and spectrum-efficient surveillance infrastructure enabled by using ADS-B in combination with other techniques,” explains SESAR’s ATM Chief David Bowen.

While commercial and general aviation operators face their own challenges, Part 25 operators come up against issues surrounding their paths to equipage and limited or costly options available to operators as they begin to seek out compliance. With a deep understanding of the regulation, a maintenance center well versed on the technology, and a head start on the mandate, business aviation operators can stay in the sky without going grey.

What You Need

“Aircraft owners should be aware that come Jan. 1 2020, the aircraft will need to have the necessary equipment to comply with the ADS-B regulations in order to fly into the airspace outlined under 14 CFR 91.225. The equipment must meet the performance requirements of TSO-C166b (i.e. DO-260B) or TSO-C154c (i.e. DO-282B) as outlined in 14 CFR 91.227,” an FAA official told Avionics Magazine.

DO-260B has been adopted as the global standard for ADS-B according to Duncan Aviation, a Maintenance, Repair and Overhaul (MRO) center that regularly performs ADS-B installations for business aviation operators. The DO-260B solution builds off of prior solutions in this vein — DO-260 and DO-260A — and incorporates improved Wide Area Augmentation System (WAAS)/GPS accuracies, latency, position forecasting developed from position and velocity to predict aircraft position, as well as additional cockpit failure annunciators among other procedures.

“The regulation requires [business aviation operators] to carry an ADS-B compliant [technology] with the Radio Technical Commission for Aeronautics [RTCA] standard DO-260B or the [European Organization for Civil Aviation Equipment] EUROCAE standard ED-102A — they are equivalent specifications — together with a navigation input from a GNSS unit with two specific named capabilities: Receiver Autonomous Integrity Monitoring (RAIM) and Fault Detection and Exclusion (FDE). Those are explicitly named in the European regulation as being the characteristics of navigation input to the ADS-B,” explains Bowen.

“When it comes down to it, a piece of equipment that is ADS-B to the 260B with a GNSS-compliant with TSO’s 145 and 146, that includes the RAIM and FDE, will satisfy both the United States and the European requirement,” Bowen adds.

Challenges Ahead

When it comes to complying with these standards, however, operators, installation centers, and regulators alike are quick to note that there is no one-size-fits-all solution.

“Each aircraft upgrade may be different. It is the ADS-B and position source combination that will make the aircraft compliant to the ADS-B regulation,” says an FAA official. “This can be as simple as a transponder software upgrade, position source software upgrade, or as complicated as a complete transponder and position source box replacement. Typically, the [Traffic Collision and Avoidance System] TCAS system is not required to be upgraded as part of the certification process to be ADS-B rule compliant.”

These differences can pose particular challenges in the business aviation arena, where one operator’s fleet often has several different avionics configurations on board each aircraft.

“It’s challenging because in the Part 25 retrofit market you see a lot of different configurations to start with, therefore there is no one cookie-cutter approach you can get to put in an ADS-B system. The integration of working with an FMS system that supports it and the avionics that require upgrades are the biggest issue. In other words, it’s not like making a cake, you kind of have to read what they have and get a detailed avionics listing in order to give an operator the best quote for his aircraft,” explains Mark Francetic, regional avionics sales manager at Duncan Aviation.

Part 25 aircraft are largely held to the same standards as the airlines in the air transport community, which means adhering to stricter requirements than Part 23 General Aviation (GA) operators, but often without an operations department to help sift out all the requirements.

“Our Part 25 aircraft have to be certified solutions, whereas the Part 23 community may have a little bit of flexibility on the aircraft on the equipment install. Part 25 aircraft need to have an approved solution installed by an authorized installer that meets a lot more requirements out of the FAA. As a Part 25 aircraft community we have got to essentially live to the same standards that the airline community lives with,” says Doug Carr, the vice president of regulatory and international affairs at the National Business Aviation Association (NBAA). Carr also notes that the FAA requires a certified repair station make the modifications to Part 25 aircraft to enable ADS-B operations.

Francetic also notes that while solutions might still be emerging for operators in other segments of aviation, it’s likely all the solutions available to operators have entered the market.

“There probably won’t be many more solutions out there for Part 25 airplanes since the STC is so cost prohibitive. It’s basically going to be the equipment offered by the manufacturer, but the prices aren’t getting any lower,” Francetic says.

Prices aside, the limited options are also causing issues for bizjet owners, particularly NetJets, which operates a fleet of more than 600 private jets. Kyle Gill, director of cockpit configuration and development at NetJets, estimates the company will have to retrofit 250 of nearly 520 aircraft that will have to comply with the upcoming ADS-B mandate — the remaining aircraft will be new additions to the fleet, already equipped with linefit ADS-B solutions. And while NetJets has already retrofit an estimated 20 percent of its fleet thus far, a lack of solutions poses an issue when it comes to complying for the mandate before the deadline.

“The big challenge for us now is that not all avionics manufacturers have the equipment or even software upgrades required. The trouble with that is that it’s difficult to get a head start on it if we equip with what is available for us. It’s between 60 and 70 aircraft per year, globally, that we have to equip with in order to get ready for the mandate. That’s a huge number,” says Gill.

“We will try wherever possible in order to align [ADS-B installations] with scheduled maintenance. This is where timing is a big factor, because if the equipment is readily available, then we can build a schedule to coincide with the aircraft maintenance schedule so that we minimize the number of airplanes that will require stand-alone events. The longer it takes for us to get started, the fewer number of opportunities there,” says Gill.

Evolving Regulation in the United States and Europe

Diagram of the ADS-B network. Photo: Duncan Aviation.

While operators are working toward equipage stated through the posted regulations for DO-260B and EUROCAE standard ED-102A, another issue is that regulatory language can be something of a moving target. Regulators in both the United States and Europe are working toward certain changes in the standards, most notably within Europe where EASA is currently working to revise the surveillance performance and interoperability regulation with the initiative to reconsider the scope and address exemption and monitoring conditions.

“Following the publication of Surveillance Performance and Interoperability regulation, the obligations for the aircraft operators to equip with ADS-B Out without a corresponding obligation for Air Navigation Service Providers (ANSP) to equip and use the ADS-B data was questioned. This, in conjunction with a U.S. equipage date, resulted in the postponement of the ADS-B mandate until June 2020 and an agreement [to] relook at the obligations,” said Brian Jolly, ATM/ANS regulations officer at EASA.

While Jolly maintains that it is too early to indicate what these changes might be and when they might be proposed, Bowen indicated it’s likely they will expand to broaden the range of aircraft required to comply. Currently in Europe, only aircraft weighing more than 5,700 kilograms and travelling faster than 250 knots are impacted, but Bowen believes this will widen. He does not believe this will have much impact on the current avionics required, however.

“I wouldn’t envisage any major changes on the avionics requirements,” he notes.

In the way of U.S regulation, guidance materials regarding the DO-260B standard, specifically AC 20-165A and AC 90-114 are also being updated.

Will the Mandate Hold?

“The number one question that I get asked is, do I think these mandates are going to hold? And from everything I’ve seen from industry, the answer to that is yes,” says NetJets’ Gill. “The FAA is very adamant that the mandates are going to be in place, so we have to plan as if they will hold.”

While there are rumors that the current Jan. 1, 2020 deadline may be pushed, the FAA and the industry experts Avionics Magazine spoke with all claimed the mandates would hold.

The FAA announced completion of the ADS-B ground network in April 2014. According to Francetic, the FAA is unlikely to push the deadline further out as it would cause funding and implementation issues.

“The FAA has constantly said they will not extend this deadline. One reason is because they’ve spent so much of their infrastructure to support this new system that is fully operational right now. To wait another five years on a system they won’t use, they will have to still support this whole aging infrastructure, which will cost them more,” Francetic says.

The perception that the FAA will give way and extend the mandate, alongside the various contributions may be contributing to a low rate of compliance, even as the mandate stands just four years out.

“There is still a very low equipage rate within the entire industry,” explains Carr. “Within the entire aviation fleet, we’re looking at something like 10 percent of all aircraft being equipped today.” Francetic urges operators and owners not to wait to comply their aircraft so as to avoid a rush to equip prior to the deadline, which he believes will result in increased pricing for both the systems and maintenance work.

“If you plan your airplanes now and schedule these for when your airplane is set to do a maintenance inspection, you can get both of those done at the same time,” he says.

The Next Step: ADS-B In

While ADS-B Out will likely offer greater benefits to the ATC system at large, coming ADS-B In technology will offer advantages to operators — when it comes available that is.

“[ADS-B In] is the capability of ADS-B on the aircraft not only to broadcast its own position for other people to use, but for that aircraft to be able to receive those transmissions from all the other aircraft and, for example, display it on the traffic display for the pilot and provide certain cockpit-based applications. Certainly, this is seen, ultimately, as the step where ADS-B starts to really deliver benefits because it allows for certain kinds of applications related to spacing to be managed on the aircraft and ultimately even separation to be managed on the aircraft itself, allowing advanced operations potentially moving to airspace where you can manage your own separation in a more effective way,” explains Bowen. Aircraft equipped with ADS-B In will have access to graphical weather displays in the cockpit as well as text-based advisories, including Notices to Airmen (NOTAM) and significant weather activity, according to the FAA’s website.

“The caveat on ADS-B In is that the current regulations both in Europe and in the United States do not include the requirement to have the ADS-B In capability,” Bowen adds.

Signal Holes

Signal accuracy regarding the ADS-B technology also poses a possible issue for airlines that demand integrity from the equipment.“From time to time there are holes in the signal coverage and, essentially, the airlines have to be able to manage around those holes,” explains NBAA’s Carr. “The airlines are willing to take on that management of those performance issues rather than setting a performance standard for the equipment higher than they would like.”SESAR’s Bowen believes that signal integrity is ingrained in the standards, which have been set to include navigation integrity, navigation accuracy, and a high level of system integrity. Essentially, he says, as long as an operator has the equipment with the systems specified by the standards, integrity and accuracy shouldn’t be an issue.“Ultimately, [signal integrity] is encapsulated in the specifications that were mentioned earlier; in particular, the requirements for the navigation source for the broadcast — being the GNSS capability with the RAIM and the fault detection and the exclusion. And it’s through these capabilities that ultimately any position information that is provided into the ADS-B unit will already be of a certain quality because of those capabilities within the GNSS system itself,” says Bowen. “That GNSS system, that meets the TSO 146, will have certain guarantees of integrity and position information accuracy because of that specification.”